Ahead of President Donald Trump’s visit to Saudi Arabia this weekend, the national chair of the 9/11 Families & Survivors United for Justice Against Terrorism advocacy group wrote a letter to the leader of the free world. The letter urges him not to buckle under pressure from Saudi Arabia and potentially weaken a provision in a law that would allow the families of victims of America’s most devastating terrorist attack to sue countries involved in carrying out terrorism.

The Sunni kingdom of Saudi Arabia has been lobbying American lawmakers to change the bipartisan law that allows the families of 9/11 victims and survivors of the tragedy to sue the Gulf Arab country in U.S. courts for any role it may have played in the 2001 attacks that killed nearly 3,000 people on American soil.

A United States law allowing victims of the September 11, 2001 attacks to sue Saudi Arabia could have “serious implications” for shared US-Gulf interests, a top Obama administration official said Thursday.

An Iraqi lobbyist group, citing the recently enacted law that allows Americans to sue Saudi Arabia over the September 11, 2001, attacks on the U.S. homeland, is reportedly urging its government to ask the United States for compensation over alleged violations by the American military following the 2003 invasion of Iraq.

The House of Representatives delivered a staggering blow Wednesday to President Barack Obama when it overrode one of his vetoes for the first time, making the Justice Against Sponsors of Terrorism Act the law of the land.

Congress is poised to override President Barack Obama’s veto of a bill that would allow families of Sept. 11 victims to sue Saudi Arabia for the kingdom’s alleged backing of the terrorists who carried out the attacks that killed nearly 3,000 people.